Switch assembly for punch card readout devices



H. C. M MILLAN SWITCH ASSEMBLY FOR PUNCH CARD READOUT DEVICES FiledApril 6, 1964 Feb. 1, 1966 2 Sheets-Sheet l INVENTOR.

C. mcmiltan Ffiguo-eg H4? aka 7 1 M ATTORNEYS g @Ell SWITCH ASSEMBLY FORPUNCH CARD READOUT DEVICES Filed April 6, 1964 Feb. 1, 1966 H. c.MCMILLAN 2 Sheets-Sheet 2 INVENTOR- Harry C. McMillan.

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3 5 I @FFQW J 4 P 4 b m m w a I I w m E- m 4 r 8 United States Patent3,233,051 SWITCH ASSEMBLY FGR PUNCH CARD READOUT DEVICES Harry C.McMillan, Cherry Hill, N.J., assignor to The Boeing Company, Seattle,Wash., a corporation of Delaware Filed Apr. 6, 1964, Ser. No. 357,462 9Claims. (Cl. 200-46) This invention concerns an improved form ofelectrical switch assembly which is adapted for use in devices havingthe function of sensing the presence or absence of pressure or of solidmedia on or within an article which may be probed by the device. Theswitch assembly is particularly adapted for collective use in so-calledpunch card readout devices which, it will be recalled, are a form ofsensing apparatus in that they are equipped with a bank of electricalswitches that operate through probing elements to examine a perforatedcard and to translate the pattern of perforated and unperforated areason the card into a corresponding pattern of electrical response incircuitry associated with the switches.

If devices of this nature are to function reliably, there must beassurance that the switches are accurately repositioned after eachreadout operation. To provide this assurance various schemes have beenadopted whereby the switches are, in many instances, released from theiractuation courses and promptly urged by springs or the like to return totheir initial stationary positions against an abutment; or in others aremore positively arrested from their courses and forcibly returned totheir stationary positions by some form of moving recovery mechanism.Still other schemes employ combinations of these. Detent means are oftenalso employed, particularly in combination with the moving recoverymechanisms, to mechanically interlock with the elements as they reoccupytheir stationary positions.

While all of these schemes are effective to reposition the switches,they often do so only at the expense of decreasing their sensitivityinasmuch as the bias or detent forces which play a part in these schemesincrease the level of pressure at which the switch can become operative.It is a principal object of the present invention to provide a switchassembly which employs neither bias nor detent forces in itsrepositioning. It is also an object to provide a switch of thischaracter which, though free from bias and detent forces, is,nevertheless, accurately and consistently repositioned following eachswitch operation.

Many of the earlier schemes for controlling the movement and positioningof the switch, also accomplished their purposes only at the sacrifice ofenlarging upon the size and complexity of the switch assembly. Anotherimportant object of the invention is to provide a switch assembly whosemovement and position are accurately and consistently controlled thoughthe switch remains extremely simple in its design and assembly.

A further object is to provide a switch assembly in which the variousfunctional requirements of the switch are concentrated into as fewelements as possible. Still further objects call for producing theforegoing switch assemblies from quick-stamped light sheet metal andmolded-plastic strip materials, and for using a mode of assembly of thesame which is readily and simply effected and which lends itself to massproduction assembly techniques. They also call for using componentswhich require no special tools in their assembly and which, in fact, canbe assembled by hand, if need be, with no more than a simple pinch toolfor attaching wires to pinch terminals.

Still another important object of the invention is to provide a switchassembly having all or certain of the Hce foregoing features and alsoofiering a choice of form between a normally closed condition and anormally open condition, and the added feature, if desired, of rapidconvertibility from one form to the other with no substantial physicalmodification of its parts. A related object is to provide such a switchassembly which can employ programmed or mixed contact forms. Still otherob ects include providing a switch assembly of these characteristicswhich not only affords the reliability of having a pure wiping action ofmetal on metal in the operatlon of its contacts, but which may alsoprovide for having at least one contact element covered at all times.

These and still other objects, advantages and features are realized by aswitch assembly of my conception making use of a unique form of shuttlepin having a lateral ear which performs both the switch function and thefunction of arresting the pin at the close of the switch operation. Theassembly comprises a pair of members constituting a switchbank and acarriage spaced above the switchbank and reciprocative with respectthereto. The shuttle pin, which is slidably guided and electricallyconductive, is connected to one side of an electrical circuit andinterposed between the members so that the end portions of its shank arereceived in mutually aligned slots in the opposing faces of the members.There are means on the carriage for holding a punch card in a positionaligned with and relatively crosswise of the slot therein so that thecard is operable, where no aperture occurs in the area of the slot, todisplace the pin in conjunction with the carriage upon the lattersoperating movement in the direction relatively toward the switchbank. Inaddition, there are also means on the carriage for displacing the pin inconjunction therewith upon the carriages return movement in thedirection relatively away from the switchbank. The ear projects laterally from the lower end portion of the pins shank, within theswitchbank slot, and there are means adjacent the switchbank slotdefining a limit stop for the ear when the pin completes itsdisplacement in the latter recited direction. The switch function isperformed by the ear as a consequence of there also being an electricalcontact member disposed in the switchbank slot at a position laterallyoifset from the path of the shank and abreast the path of the ear. Thecontact member is connected to the other side of the circuit and biasedin a direction crosswise of the ears path so as to alternately engageand disengage the ear as the pin is reciprocated with the carriage.

Because of these structural and positional relationships, the contactmember can be shifted to alternative positions-abreast the path of theear spaced lengthwise of the switchbank slot. In this way the assemblycan ernploy programmed or mixed contact forms. In my more preferredconstructions, the switchbank slot has a longitudinal recess in the sidewall thereof and the ear is received in the recess to abut with thelimit stop provided by the upper end wall of the same, in the stationarycondition of the carriage, the contact member being disposed in therecess and shiftable to alternative positions spaced lengthwise of thesame. In addition, the lower end of the recess may open onto the underside of the switchbank and the contact member may include means by whichit is shiftable from a point outside of the switchbank.

Certain of these more preferred constructions are described in greaterdetail hereafter with reference to the accompanying drawings wherein:

FIGURE 1 is an exploded view in perspective of one embodiment made up inmultiple units for use as a switch block in a punch card readout device;

.FIGURE 2 is a pair of sectional views taken at right angles to oneanother through an individual unit for purposes of illustrating theswitch assembly in its normally closed condition;

FIGURE 3 is also a pair of sectional views taken at right angles to oneanother for purposes of illustrating the actuated condition of theswitch assembly in FIGURE 2 where the probed region or area of the puncharea has no aperture;

FIGURE 4 is a similar pair of views illustrating the switch actuatedcondition where the probed region or area of the card presents anaperture;

FIGURE 5 is a further set of views illustrating an individual switchassembly disposed in the normally open condition;

, the abutting faces of the strips 11 is grooved. In the case FIGURE 6illustrates the switch actuated condition of the assembly in FIGURE 5where no aperture appears in the card; and

FIGURE 7 illustrates a modified form of the embodiments of FIGURES 16whereby the switch assemblies can be readily converted from a normallyopen to a norma-lly closed condition or vice versa from below the switchblock.

Referring first to FIGURE 1, it will be seen that the 'switch blockcomprises a pair of relatively superposed and relatively reciprocativemembers B and C. The lower B of the members serves as a stationaryswitch bank and the upper C serves as a reciprocative carriage for theshuttle pins S which, in this instance, have a thin, flat, elongatedform. The members B and C can be mounted, guided and relativelyreciprocated in any conventional fashion, there being a large selectionof means and techniques for this purpose in the prior art.

The carriage C hastwo parts or components C1 and C2 which are connectedfor conjoint reciprocation by means not shown. As seen the lower C1 ofthe two parts is in the form of a block having a number of rectangularlycross-sectioned slots or channels 2 which are vertically oriented inspaced, parallel ranks in the block and extend through its entire depth.In use the slots serve as guideways for the pins S and as such will bereferred to as the pin guide slots. The lower part C1 also serves aswitch return function which will be discussed hereinafter. The upperpart C2 is in the form of a platen which is transversely grooved alongits underside, the grooves 4 being disposed in parallel relationship toand vertically above the ranks of the pin guide slots 2 in the lowerpart. In their mounting the two parts C1 and C2 are spaced from oneanother so as to define a reception slot R for a punch card P. The cardis inserted into the slot R in a known manner so that its pattern ofapertured and nonapertured areas is interposed between the ranks of thepin guide slots 2 and the grooves 4 thereover. See FIGURES 2-6 in thisconnection.

The switch bank B is likewise characterized with a coplanar array ofvertical, rectangularly cross-sectioned slots or channels 6 which areequal in number to the overhead pin guide slots 2 and aligned with thelatter in their distribution. As will be seen, these lower slots 6 inthe switch bank operate to receive the inferior or descending ends 8 ofthe shuttle pins S and also serve to house a pair of contact members M1and M2 which are received in the slots 6 from below the switch bank. Thecontact members are capable of assuming either a normally closed or anormally open condition. In the contact form illustrated in FIGURE 1 thetwo contact members present a normally closed condition as will beexplained, and in addition contribute to a nip which is developed in theslots 6 for the pins, as will also be explained.

It should be mentioned beforehand, however, that each of the switch bankB and the lower carriage component C1 is constructed from a plurality ofmolded insulative plastic strips 10 and 11, respectively, which aresupplied with transverse grooving 13 and 15 so that when placed uprightand clamped abreast of one another in a horizontal and lengthwise sense,as illustrated, their abutting faces 12 and 12', and 14 and 14',respectively, act to define the of the switch bank, both abutting faces12 and 12 are grooved and two sets of molded plastic, insulative keys 16and 18 are interengaged with the strips .in additional grooves 20 andrabbets 22 formed in their abutting faces. The additional grooves 20 runlengthwise and horizontally of the strips 10 in the assembly so as totraverse the vertically oriented grooves 13 therein. One set of the keys16 is received in these additional grooves and as will be laterexplained serve a separator and locator func tion for the contactmembers M1 and M2 inserted into the slots 6. The rabbets 22 are formedin only one of the upper edges of the abutting faces of the strips 10and in effect leave benches 24 on which the second set of keys 1% areallowed to rest, the rabbets 22 and keys 18 being mutually sized toleave the latter flush with the upper face of the switch bank B.Functionally, this second set of keys 18 serves as a set of limit stopsor bumpers to be more fully described hereinafter.

The pin guide slots 2 and the switch bank slots 6 have still furtherconfigurational features. In the case of the former it will be notedthat the upper end portions of the slots are recessed to one side so asto form steps 26 for a function to be described. As for the switch bankslots, projections 28 are permitted to remain on their side walls atopposing locations in the assembly for a locator function to bementioned.

Reference should now be made to the pins S and the contact members M1and M2. Each of the pins has an elongated center shank portion 30 whichin the assembly is slidably received and guided in the lower end portionof one of the pin guide slots 2. At each end of the shank portion thepin has a lateral extension furnishing it with upper and lower ears 32and 34, respectively, between which the pin in effect has a relievedlongitudinal profile.

In the assembly the upper ear 32 is normally received in the pocket orrecess 36 formed above the step 26, so that the step and the ear form apair of cooperable abutment shoulders. At the other end of the pin, itslower ear 34 is received in the well or recess 38 formed below theunderside 18 of the key 18. Thus the lower ear 34 is in a position toperform in cooperation with the underside 18' of the key 18 as anadditional set of abutment shoulders which, as will be seen, operate ina reverse directional sense from the pair of abutment shoulderscomprising the step 26 and the upper ear 32.

Each of the contact members M1 and M2 takes the form of a flat elongatedtongue 40 the lower ends of which in the assembly are shaped to act aspinch terminals 42 for a pair of wires W leading to the members and theupper ends of which are laterally deflected to leave transverse ribs 44and 46 outstanding on the tips of the tongues. Also, the relativelyadjacent and remote longitudinal edges of the tongues are notched atcorresponding locations so that the contact members can be located intheir slot 6 through engagement of the projections 28 in their notches48 and engagement of the keys 16 in their notches 50. To also separatethe contact members M1 and M2 by an insulative air gap, the latternotches 50 have a depth of less than a half thickness of the key 16 thuspreventing the members from engaging one another.

Each of the pins S and the contact members M1 and M2 is made from anelectrically conductive light sheet metal material and can beconveniently stamped from such material for its use in the illustratedassembly.

Referring at once now to FIGURES 1-4, it will be noted that the tongues40 of the contact members are of such length above of the location ofthe projections 28 as to position their ribs at a level or station justbelow the lip or inverted shoulder formed by the underside 18 of the key18. Note also from the cross sectional views of FIGURE 2 that the lowerear 34 of the pin bridges the air gap between the ribs 44 and 46 of thecontact members. Note still further that the ribs close upon this lowerextremity of the pin when it is drawn up into their station and by theirbending action in cooperation with the opposite wall 52 of the slot forma nip exerting a slight gripping or pinching action on the pin. Thisconstitutes the normal or stationary osition of the pin. In theoperation of the assembly, when the carriage C is displaced relativelytoward the switch bank B, the card P abuts the pin and depresses itfurther into the slot 6 so as to displace the ear 34 thereon relativelyout of the nip formed by surfaces 44, 46, 52. See FIGURE 3. The step 26is also depressed but due to a slight initial gap between the pin andthe card, finds itself slightly below the car 32 at the close of thecarriages downstroke. On the carriages upstroke, however, the stepreengages the ear and serves to lift the pin back into the nip betweensurfaces 44, 46, 52. Progress of the pin beyond the position in whichits ear 34 is disposed in the nip, is prevented by the key 18 whoseunderside 18 forms an abutment for the ear 34.

In the at rest condition of FIGURE 2 the upper car 32 of the pin restson the step 26 and a slight gap is seen between the key 18 and the lowerear 34 of the pin. In operation the ear 34 may in fact never reach thekey 18 as it enters the nip but the likelihood is greater that theuplifting action of the carriage and its abrupt halt will bring the key18 into operation as a means of stopping the pin through its lower ear3:4. The pin will eventually thereupon settle back into its at restcondition as illustrated. In no case will it exert undue pressure on thecard P. Note that the gap between the upper edge of the pin and theunderside of the card is considerably larger to assure that the card isat no time given a blow by the pin.

Now consider FIGURE 4. Where an aperture appears in the card the pinremains in its stationary position frictionally engaged at the hands ofthe rib and wall surfaces and the carriage merely reciprocates over thelength of the pin, the upper extremity of the pin being taken up by theoverhead groove 4 in the platen C2. Thus whereas in the former instancethe circuit otherwise closed between the ribs by the pin, was openedwhen the carriage was depressed, in the latter instance the circuitremains closed as relative reciprocation occurs between the pin and thecarriage.

Obviously, only the left hand rib 44 is necessary to the nip acting onthe pin; consequently, where current is passed in or out of the ear 34by other means (as by a flexible lead to the same) the right handcontact member M2 can be removed. However, the illustrated arrangementis much preferred not only because the contact provided through theright hand rib 46 is at all times shrouded by the pin, but also becausethe additional frictional engagement made with the pin through this ribis at all times present to steady the pin and to maintain better controlover its shuttle action in the assembly. The right hand rib 46 in factacts to keep the pin and the card continuously engaged until the latteris withdrawn in the return stroke of the carriage.

The versatility of the assembly is illustrated by FIG- URES 5 and 6.Where the left hand contact member M1 is of shorter length than theright hand member M2 a normally open condition is obtained due to thelower disposition of the rib 44 on the left hand member. The assemblyoperates the same otherwise, the depressed condition of the pin servingnow, however, to close the circuit, as seen in FIGURE 6. Obviously, thenon-aligned or offset relationship of the ribs can also be gainedthrough an adjustment made in the relative positioning of the locatorprojections in the slots 6 and the notches in the contact members.

In fact, as seen by FIGURE 7, steps can be taken to make the mechanismconvertible from one form to the other even while in a fully assembledstate. In this instance each of the notches 48", 50 made in the lefthand contact member M1" has been enlarged lengthwise of the member and apair of holes 54 has been provided in the lower end portion of thetongue 40''. The latter has also been lengthened so that the position ofthe rib 44 on the member M1 can be adjusted from below the switch bankby first disengaging the member from a pin 56 passed through one of theholes 54 and thereafter shifting the member up or down in the slot. Thepin 56 is supported on a bracket 58 and may be nothing more than ashallow button over which the member is sprung and engaged; or it may beof considerably greater length and may, in fact, pass through a row ofsimilar contact members, it thus being necessary first to disengage thepin from other assemblies before shifting the member M1.

The choice will depend on the circumstances under which the switch blockis to be employed.

Obviously, the contact members can be otherwise located in the switchbank slots, as, for example, by additional grooving made in what are thewalls of the slots as seen. The invention is likewise susceptible tomany other modifications and additions, all of which can be made withoutdeparting from the spirit of the invention as defined in the claimsfollowing.

I claim as my invention:

1. In combination, a pair of members constituting a switchbank and acarirage spaced above the switchbank and reciprocative with respectthereto, the opposing faces of the members having mutually aligned slotstherein, a slidably guided electrically conductive shuttle pin connectedto one side of an electrical circuit and interposed between the membersso that the end portions of its shank are received in the slots, meanson the carriage for holding a punch card in a position aligned with andrelatively crosswise of the slot therein so that the card is operable,where no aperture occurs in the area of the slot, to displace the pin inconjunction with the carriage upon the latters operating movement in thedirection relatively toward the switchbank, and means on the carriagefor displacing the pin in conjunction therewith upon the carriagesreturn movement in the direction relatively away from the switchbank,there being an ear projecting laterally from the lower end portion ofthe pins shank, within the switchbank slot, means adjacent theswitchbank slot defining a limit stop for the ear when the pin completesits displacement in the latter recited direction, and an electricalcontact member disposed in the switchbank slot at a position laterallyoffset from the path of the shank and abreast the path of the ear, whichcontact member is connected to the other side of said circuit and biasedin a direction crosswise of the ears path so as to alternately engageand disengage the ear as the pin is reciprocated with the carriage.

2. The combination according to claim 1 wherein the contact member isshiftable to alternative positions abreast the path of the ear spacedlengthwise of the switchbank slot.

3. The combination according to claim 2 wherein the switchbank slot hasa longitudinal recess in the side wall thereof and the ear is receivedin the recess to abut with the limit stop provided by the upper end wallof the same, in the stationary condition of the carriage, the contactmember being disposed in the recess and shiftable to alternativepositions spaced lengthwise of the same.

4. The combination according to claim 3 wherein the lower end of therecess opens onto the under side of the switchbank and the contactmember includes means by which it is shiftable from a point outside ofthe switchbank.

5. The combination according to claim 1 wherein the switchbank isconstructed from a plurality of vertically oriented strips havingabutting faces of which at least one is grooved to define the slot forthe pin, there being a key disposed across the upper end of the slot, toone side of the pins shank, to define the limit stop for the ear.

6. The combination according to claim 1 wherein the contact member takesthe form of a thin flat elongated tongue disposed lengthwise in theswitchbank slot at a position abreast the path of the ear, and one endof the tongue is biased in the direction crosswise of the ears path.

7. The combination according to claim 6 wherein the pin is thin and flatin the lengthwise direction and there is a second thin flat elongatedelectrically conductive tongue disposed lengthwise in the switchbankslot at a position abreast the path of the pins shank, said secondtongue being connected to the one side of the circuit and biased at oneend in a direction crosswise of the shanks path so as to continuouslyengage the pin as it is reciprocated with the carriage.

8. The combination according to claim 7 wherein there is a transverserib on each of the tongues having a bend- References Cited by theExaminer UNITED STATES PATENTS 2,825,773 3/1958 Avdeenko 200 463,062,326 11/1962 Jones et a1. 20061.19 X 10 3,166,648 1/1965 Sodermanet a1. 200-46 ROBERT S. MACON, Acting Primary Examiner.

ROBERT K. SCHAEFER, Examiner.

15 WILLIAM C. GARVERT, Assistant Examiner.

1. IN COMBINATION, A PAIR OF MEMBERS CONSTITUTING A SWITCHBANK AND ACARRIAGE SPACED ABOVE THE SWITCHBANK AND RECIPROCATIVE WITH RESPECTTHERETO, THE OPPOSING FACES OF THE MEMBERS HAVING MUTUALLY ALIGNED SLOTSTHEREIN, A SLIDABLY GUIDED ELECTRICALLY CONDUCTIVE SHUTTLE PIN CONNECTEDTO ONE SIDE OF AN ELECTRICAL CIRCUIT AND INTERPOSED BETWEEN THE MEMBERSSO THAT THE END PORTIONS OF ITS SHANK ARE RECEIVED IN THE SLOTS, MEANSON THE CARRIAGE FOR HOLDING A PUNCH CARD IN A POSITION ALIGNED WITH ANDRELATIVELY CROSSWISE OF THE SLOT THEREIN SO THAT THE CARD IS OPERABLE,WHERE NO APERTURE OCCURS IN THE AREA OF THE SLOT TO DISPLACE THE PIN INCONJUNCTION WITH THE CARRIAGE UPON THE LATTER''S OPERATING MOVEMENT INTHE DIRECTION RELATIVELY TOWARD THE SWITCHBANK, AND MEANS ON THECARRIAGE FOR DISPLACING THE PIN IN CONJUNCTION THEREWITH UPON THECARRIAGE''S RETURN MOVEMENT IN THE DIRECTION RELATIVELY AWAY FROM THESWITCHBANK, THERE BEING AN EAR PROJECTING LATERALLY FROM THE LOWER ENDPORTION OF THE PIN''S SHANK, WITHIN THE SWITCHBANK SLOT, MEANS ADJACENTTHE SWITCHBANK SLOT DEFINING A LIMIT STOP FOR THE EAR WHEN THE PINCOMPLETES ITS DISPLACEMENT IN THE LATTER RECITED DIRECTION, AND ANELECTRICAL CONTACT MEMBER DISPOSED IN THE SWITCHBANK SLOT AT POSITIONLATERALLY OFFSET FROM THE PATH OF THE SHANK AND ABREAST THE PATH OF THEEAR, WHICH CONTACT MEMBER IS CONNECTED TO THE OTHER SIDE OF SAID CIRCUITAND BIASED IN A DIRECTION CROSSWISE OF THE EAR''S PATH SO AS TOALTERNATELY ENGAGE AND DISENGAGE THE EAR AS THE PIN IS RECIPROCTED WITHTHE CARRIAGE.